There are known many multi-bit tools in which multiple driver bits can be stored and selected for use. Some of the simplest such as U.S. Pat. No. 4,273,173 provide storage for multiple driver bits, a selector allowing the desired bit to be retrieved from the storage portion of the tool and manually placed into the driving socket of the tool. This involves extracting the driver bit from the storage location and then manually fitting it into the driving socket of the hand tool.
Other more sophisticated multi-bit tools are also known in which the working bits may be interchanged without having to remove them from the tool. For example in U.S. Pat. No. 4,572,038 the bits are stored in a magazine mounted eccentrically on the main drive axis of the tool. The magazine allows the bits to be rotated to position the desired bit in line with the main drive axis of the tool where an inner shaft engages with the bit, allowing that desired bit to be extruded from the end of the main drive axis of the tool for use. However, as the magazine is eccentric, if it rotated with the bit in use, the tool would be unstable at speed (ie for use with a power tool such as a powered drill), so the magazine can remain stationary, with the shaft driving the bit inside a sleeve portion of the tool, but that requires the shaft to drivably engage with the bit, requiring specialised or proprietary bits (ie conventional bits, as available and interchangable with hex-drive hand and powered drills and drivers, would not work in this prior invention).
A further example of a multi-bit driver is disclosed in U.S. Pat. No. 4,480,668. Again the bits are stored in an eccentric magazine with one bit position in line with the main drive axis of the tool, the magazine being rotated inside the handle of the tool through an access hole in the side of the handle. To load a bit from the magazine, the desired bit position is selected by rotating the magazine inside the tool, then the tool is held with the hex drive socket pointing downwards so gravity allows the bit to slide out of the magazine into the drive socket, the drive socket including a spring loaded ball type clamping head which must be operated to allow the bit to reach the operating or working position and be locked there axially. Similarly returning a bit to the magazine requires operation of the clamping head and inverting the tool, handle downwards, so that gravity can return the bit into the magazine in the handle. Although this tool can use conventional bits, it is not designed for use with power tools having an incompatible construction and interchanging bits requires the whole assembly to be inverted.
There is a further deficiency common to all the prior art—that is the maximum hex drive size is limited by the size of the bits being stored.
It is therefore an object of the present invention to provide a multi-bit tool which overcomes one or more disadvantages of the prior art.
It is an optional object of the invention to provide a hex drive larger than the size of the bits being stored.